Ceramic fiber reinforced ceramic matrix composite material and method of producing the same

Abstract

According to a ceramic fiber reinforced ceramic matrix composite material of the present invention, a ceramic fiber reinforced ceramic matrix composite material 1 comprises a composite ceramic matrix, and a preform 5 resulting from a fiber bundle 3 obtained by bundling a plurality of ceramic fibers 2 and disposed therein, and is characterized in that a first ceramic matrix M1 is formed in an inner space of the fiber bundle 3 and at a region adjacent to an outer periphery thereof, and a second ceramic matrix M2 is formed in an inner space of the preform 5 and at an outer peripheral region thereof, the space and region of the preform being defined except for those of the fiber bundle. Also characteristically, ceramic fibers are compositely disposed in a fiber volume fraction (Vf) of greater than 10% in a reaction-sintered ceramic matrix. It is further preferred that the composite material be provided on a surface thereof with a coat layer composed solely of a ceramics and having a thickness of not less than 50 mum.

What is claimed is:  
     
       1. A ceramic fiber reinforced composite material comprising a ceramic matrix, and a fiber preform obtained by bundling a plurality of ceramic fibers into yarn wherein a first ceramic matrix is formed in the inner spaces of said yarn, and a second ceramic matrix is formed in the inner spaces of said fiber preform. 
     
     
       2. A ceramic fiber reinforced composite material according to claim  1 , wherein said first ceramic matrix is composed of a ceramic derived by synthesizing a main ingredient of a ceramic precursor as a starting material which is convertible into a ceramic upon calcination, and said second ceramic matrix is composed of a ceramic obtained with use of a powder ceramic as a starting material. 
     
     
       3. A ceramic fiber reinforced composite material according to claim  1 , wherein said first ceramic matrix is composed of a ceramic derived by a chemical vapor infiltration method (CVI method), and said second ceramic matrix is composed of a ceramic obtained with use of a powder ceramic as a starting material. 
     
     
       4. A ceramic fiber reinforced composite material according to claim  1 , wherein said first and second ceramic matrices are composed of ceramics obtained with use of a powder ceramic as a starting material, and said first ceramic matrix has an average crystalline particle diameter that is smaller than that of said second ceramic matrix. 
     
     
       5. A ceramic fiber reinforced composite material according to claim  1 , wherein each of said ceramic fibers is a continuous fiber having on its surface a slide layer containing at least one material of carbon (C) and boron nitride (BN). 
     
     
       6. A ceramic fiber reinforced composite material according to claim  1 , wherein said first and second ceramic matrices a composed of a ceramic having a main ingredient of the same composition. 
     
     
       7. A ceramic fiber reinforced composite material according to claim  1 , wherein said first ceramic matrix is formed by means of reaction sintering. 
     
     
       8. A ceramic fiber reinforced composite material according to claim  1 , wherein said second ceramic matrix is formed by means of reaction sintering. 
     
     
       9. A ceramic fiber reinforced composite material according to claim  1 , wherein said composite material has a void fraction of not larger than 10% by volume. 
     
     
       10. A ceramic fiber reinforced composite material comprising a ceramic matrix and a fiber pre-form obtained by bundling a plurality of ceramic fibers into yarn, wherein a first ceramic matrix is formed in the inner spaces of said yarn, and a second ceramic matrix is formed in the inner spaces of said fiber pre-form said ceramic fibers are disposed at a fiber volume fraction (Vf) of greater than 10%, and either one of the first ceramic matrix and the second ceramic matrix is a reaction-sintered ceramic matrix. 
     
     
       11. A ceramic fiber reinforced composite material according to claim  1  or  10 , which has on a surface thereof a coating layer composed solely of a ceramic having a thickness of at least 50 μm. 
     
     
       12. A ceramic fiber reinforced composite material according to claim  10 , wherein each of said ceramic fibers is a continuous fiber having on its surface a slide layer containing at least one material of carbon and boron nitride (BN). 
     
     
       13. A ceramic fiber reinforced composite material according to claim  5  wherein an interfacial layer is disposed at the interface between said slide layer and said ceramic matrix, said interfacial layer being composed predominantly of at least one material of Si 3 N 4 , SiC and SiO 2  and having a thickness of more than 0.1 μm. 
     
     
       14. A ceramic fiber reinforced composite material according to claim  13 , wherein said interfacial layer is obtained by a CVD method.